Apparatus for defibering and deinking papers



All@ 19 1941. H. PARTINGTON. Erm. 2,252,781

APPARATUS FOR DEFIBERING AND DENKING PAPEVRS Filed Feb. 1o, ywas N S RTOIT OGT w. TNI T` NR. T E.TR. A VRO NADI H .,v DM A|h WL DI! 1 EW l H N krf Patented Aug. 19, 1941 ullrlsznl YsTATEs PATENT' OFFICE c ressaisir` A Henry Partingtonfwembley, and William lElrilry Perritt, Chilcompton, near Bath, Eng- Appuesnonrebmary 1n, 193s, serial- No. rsasso In Great Brum seam" 1o, 1931 y l Claim.

y The present invention concerns the treatment of materials such as paper,l paper board, and the like nbrous products for the purpose of recovering therefrom, inter alia, the fibrous constituents in a form in which they may be reutilised for the manufacture of paper, paper board, etc., and has particular reference to an apparatus whereby the said brous constituents may be recovered from printed waste papers and paper boards, in a clean, ink-free condition and also free from the'other materials associated therewith in the paper, paper board and the like.

The treatment of paper and paper board espe- Vcially when these are printed, in order to obtain a clean pulpV therefrom involves, broadly speaking, three separate considerations, firstly there must be a suitable pretreatment whereby the led to assist in softening the paper or if desired in the modification thereof. For example caustic alkali maybe employed and this may be introduced at the commencement of the steeping-operation or in the course thereof, The nature of the steeping operation'may, for example, depend upon the character of the paper or -paper board `under treatment, and where this is old andy has -become modified due to the formation of oxypaper or paper board can be brought into condition suitable for further mechanical treatment whereby the material can be denbered. This initial treatment must also be such as to facilitate the separation of any ink and llers from ,the paper and enable these to be removed by straightforward washing. The second consideration is the nature of the mechanical treatment to which the pretreatedmaterial is to be subjected. This mechanical treatment mustbe anchas completely to deilber the paper, while at the same time not paper board or the like is subjected to a steeping-V operationF in a suitable steepifng liquor, whereafter it `is Asubjected to mechanical treatment adapted to separate the fibers one from the other; and\from the associated materials such as fillers, ink, size, loading and thelike, but without damaging the fiber or shortening the mean fiber 'I'he third-concelluloses, the treatment with caustic` soda or other suitable reagents` such as alkali and alkaline earth salts of weak acids may be delayed until alater stage of the' steeping process. In some circumstances it may bej found desirable to incorporate wetting agents in the steeping solution. Thus, for example, if the paper contains Oxy-cellulose in substantial quantities due to ageing and/or is heavily printed, it is found that an initial aqueous steeping materially assists in loosening the print whereas if caustic soda is added at the outset, the fibers immediately in contact with the ink do not respond so readily to disintegration by the later steps. Thus in some instances it isaadvantageous if the treatment with caustic soda and like reagents is delayed to a later stagein the steeping operation.

The steepingstep may if desired be carried out with heating for example to about 1GO-200 F.

this being found to shorten the operation consid- The second stage of the preferred operationy consists in subjecting the steeped material to mechanical disintegration and according to theV f of the material under treatment. To this fact length unduly, this separation being so effected that the associated materials may readily-be removed from' the ber by a simple washing operation, the 'ber being then cleaned by such a vwashing operation. l f i 4'lo this end-the invention provides a machine whereby a suspension of'paper is operated on to form a stream'or streams so directed that suiii- .may be ascribed the valuable result that the ink initially present on the surface of the bers becomes detached and not beaten into the surface of the aber rendering it dimcun to 'wasn the pulp clean after ,disintegration is completed.

In conducting this stage of theoperation,

therefore, an apparatus isused in which the soaked paper, paper board or the like is caused to move in suspension at a suitable concentration, for exam 1e 5 to 10% by weight and in `such a way that at ne or more pointsin the course of its movement the suspension is converted into a 2 I y V l stream which is caused so to interact in opposition with another portionof the suspension that a considerable abrasive or disintegrating action is set up between the fragments of paper, paper -board and the like in the neighbourhood of the interaction. It is found fin pactic'e that actually complete debering and de-inking is achieved above a certain minimum. of agitation inthe rnanner indicated.

The suspensions'so treated may readily be deflbered and dednked in the manner indicated in an economic period of minutes, provided that the initial steeping operation is carried out correctly, and thereafter may be readily washed so as to provide va pulp which is substantially indistinoriginally made. l

The invention will be described with reference to the attached drawing which illustrates an embodiment of my improved apparatus for disintegrating paper and the like. v Iii the drawing there dis shown an'embodiment tice to work satisfactorily and to permit of repeated batch handling without trouble. In'this device a cylindrical barrel a is provided with a lateral inlet b Vfor the. suspension and an outlet c returning the treated pulp to acontainer d in such manner that the whole of the lbatch con- 'taired in the apparatus circulates uniformly through the barrel. For. this purpose the containerI d is provided with a central sleeve h arranged as shown' and the inilowing suspension ,*circulating around it flows into the sleeve at the upper end. `Within the barrel driven on a comof friction between the suspendedfragments must be attained to cause satisfactory disintegration of the paper and consequently there is a min- `imum speed of rotation of@ the firstmentioned I .guishable from the pulp from which the paper f or paperboard' forming the raw materialwas lof' the invention which has been found in pracpropeller I. At the same time this degree of friction is only set up if therev is a :sufficient flow into the barrel. On the other hand if due to the second-mentioned propeller a the flow is rendered too great the centrifugal stream from the first-mentioned .propeller finto the inlet may be partly or entirely suppressed Vwith the consequent 'v result that no deflbering of a satisfactory character occurs.

In a particular case the barrel had an internal diameter of 4". The mst-mentioned propeller f had a pitch of ths inches and the second g a pitch of '1% inches, being otherwise similar to the first both being two bladed. To secure a sufficient freedom from direct interaction of one propeller on the other they are spaced some distance apart. In theapparatus in question af distance of 91/2 inches between the propellers is satisfactory and it was found that results did not improve if this distance was increased .while if the propellers were noticeably closet the results deteriorated-ac-` cordingly. s With the dimensions given above the optimumA effect for deflbering and de-inking of waste paper was foundat a speed of revolution of the propellers of 2665. R.. P. M. \If this speed is not at-V .tained then the friction in the inlet requisite to secure adequate defibering is apparently lacking. If the speed is exceeded materially there is at a point slightly removed in the direction of flow through the barrel from -the point at which the axis of the feed inlet intersects the axis of the barrel (assuming the simple case where axes are concurrent).y In general this displacement ywillfbe approximately th of an inch', this figure effect a stream of the suspension into thelinlet Y .which consequently opposes the flow of material into the barrel. Thus while this mst-mentioned propeller lhas some tendency to' feed the material through the barrel'due toits position in the inlet, it will not cause eiilcient circulation of the vmaterial. Consequently the second-mentioned propeller a is provided in order to secure a satisfactory flow through the apparatusconsistent with the maintenance of the opposing streams in the inlet to the barrel. The ratio bet een the pitch of the propellers and. also the absolu e pitch of the propellers must be carefully controlled in relation to the speed atwhich the propellers are driven. Thus in the first place a certain degree it'beconies limpossible wholly to cleanse apparently a tendency for the second-mentioned propeller' to suppress the centrifugal stream from he first-mentioned propeller with the result that emciency againfalls on. It is found that the ratios above suggested, the general dimensions and the speed of rotation'of the propellers does not alter materially with increase in the size of the plant but it is particularly important however that the displacement of the first-mentioned propeller in the inlet conforms'substantially with the gures given above. I

It is however to be noted that these figures have been determined with relation to a cylindrical inlet and a cylindrical barrel of substantially the same diameter, the axes of-the barrel 'and inlet being concurrent. lIf'the form of the barrel varies in cross section and/or if the form of the inlet varies in cross section or if the ratio betweenthe diametersiof the barrel and inlet vary, or their axes are not concurrent, then the proportions and values given above may require modification which is best determined by experiment.' The principle however should be to create in the inlet a sufficiently vigorous interaction of,

opposing streams of-suspensioJn-to leilect disin- In all cases care must betaken to avoid beating `of the pulp by mechanical members as far aspossible since this. apart from breaking upI the fiber, has also a tendency to beat the ink particles into the fiber rather than to loosen ysaid particles from the ber. 'This is shown clearly by the fact that if the machine is operated for too long a period upon a given batch of material the ma# teria! from ink bywashing. f

` It may be'rnentioned that the washing out-- of the ink from debered pulp made from printed raw materials is considerably facilitated by the presence ofthe fillers yand loading materials in the raw 'Illhusy where it isfdesired for example to treat printed papers'which contain little or no loading such as newsprint it is advantageous to use a ,suspension of ne material such as china clay to assist in the Washing out of the ink.

A further useful application of the apparatus of the invention is in the production of particular varieties of cellulose from raw material of mixed character. Such particular varieties of cellulose are required for certain specic purposes, for example, in the manufacture of explosives. It is found that by suitable modification of the conditions of steeping and the solution used therefor and of the conditions of treatment during the defibering operation, eiectiveseparation of the constituents of the raw material cellulose can be achieved. For example stronger caustic soda may be used to effect at least a partial separation of the varieties of cellulosewhich may be present. f

We claim:

In an apparatus for defibering and de-inking aqueous suspensions of steeped and partially disintegrated brous materials of the character ofl paper; the combination of a reservoir adapted to hold a substantial body of said suspension, a cyclic channel originating in said reservoir at a point below the normal liquid level in said reservoir and at its other end returning to said reservoir, said channel comprising a relatively straight barrel section disposed at a level lower than said reservoir and an inlet section arranged to intersect with said barrel 4section at a relatively sharp angle, a `propeller mounted in said channel in the zone formed by the intersection' of said barrel section and said inlet section with vits axis of rotation parallel to the axis of said axis of rotation parallelto the axis of said barrel said second mentioned propeller being positioned at a. substantial distance axially from the nrst mentioned propeller, and means for rapidly rotating said second mentioned propeller in a direction tending to force liquid through said barrel section away from the zone of intersection with said inlet section. 4

EDWARD HENRY PARTINGTON. WILLIAM HENRY PQRRI'II'. 

